Reader disagrees with Schoch's palaeometeorological estimates, and instead concludes that the Sphinx dates to the Early Dynastic Period (c. To explain the disproportionate size of the head compared to the body, Reader, as does Schoch, also suggests the head of the Sphinx was originally that of a lion and recarved sometime later in the likeness of a pharaoh.
Similarly, David Coxill, a geologist working independently of both Schoch and Reader, has concluded from the evidence of weathering in the enclosure that "[t]he Sphinx is at least 5,000 years old and pre-dates dynastic times [before 3100 BC]." Zahi Hawass, former Egyptian minister of state for antiquities affairs and secretary-general of the Supreme Council of Antiquities, was asked in an interview on the PBS series NOVA if it was possible that a more ancient civilization might have sculpted the Sphinx.
600 BC), and notes that the entrances of the tombs have weathered so lightly that original chisel marks are still clearly visible.
He points out that if the weathering on the enclosure walls (up to a metre deep in places) had been created by any of the proposed alternative causes of erosion, the tomb entrances would have been weathered much more severely.
From his investigation of the enclosure's geology, Schoch concluded the main type of weathering evident on the Sphinx enclosure walls was caused by prolonged and extensive rainfall.
According to Schoch, the area has experienced a mean annual rainfall of approximately one inch (2.5 cm) since the Old Kingdom (c.
Peter Lacovara, an Egyptologist and curator at the Michael C.
Carlos Museum at Emory University, Atlanta, assigns "some of the erosional features" on the enclosure walls to quarrying activities rather than weathering, and states that other wear and tear on the Sphinx itself is due to groundwater percolation and wind erosion.Obviously, if the limestone cores (originating from the Sphinx ditch) of the temples predate the granite ashlars (granite facings), and the granite ashlars are attributable to Khafre of the Fourth Dynasty, then the Great Sphinx was built prior to the reign of Khafre." Colin Reader, a British geologist, agrees that the suggested evidence of weathering indicates prolonged water erosion.Reader found, inter alia, that the flow of rainwater causing the weathering had been stemmed by the construction of 'Khufu's quarries', which lie directly "upstream" of the Sphinx enclosure, and therefore concludes that the Sphinx must predate the reign of Khufu (2589 – 2566 BC), and certainly Khafra, by several hundred years.John Anthony West, an author and alternative Egyptologist, investigated Schwaller de Lubicz's ideas further and, in 1989, sought the opinion of Robert M.Schoch, a geologist and associate professor of natural science at the College of General Studies at Boston University.Lehner points to the way several structures in the area incorporate elements from older structures, and based on the order in which they were constructed concludes that the archaeological sequencing does not allow for a date older than the reign of Khafra.